Evidence based medicine and policy



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Evidence based medicine (EBM) has been defined as the a process of turning clinical problems into questions and then systematically locating, appraising, and using contemporaneous research findings as the basis for clinical decisions.'1 The phrase ‘evidence-based’  was coined by David Eddy, an American healthcare analyst, in the 1980s, and the term ‘evidence-based medicine’ was first used by Gordon Guyatt, a professor in the Department of Epidemiology at McMaster Medical School in Canada, in 1990 to label this clinical learning strategy.

It marks a shift from basing clinical decisions on out-of-date teaching or experiences with individual patients, to incorporating the results of the most recent knowledge from rigorous clinical studies into the decision-making process. At worst, delays in adoption of research evidence into clinical practice can mean patients receive expensive, ineffective, or even harmful treatments. Recognition of this has been one of the driving forces behind the development of evidence-based medicine.1,3

The practice of evidence-based medicine means integrating clinical expertise and the best available evidence from systematic research with the ideas, concerns and expectations of individual patients. This includes clinically relevant research into the accuracy and precision of diagnostic tests, the power of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventative regimens. EBM is not restricted to randomised controlled trials and meta-analyses, but should involve appraising the best evidence available with which to answer clinical questions.2

Research literature is constantly changing, and the volume of health information has increased rapidly. The growth of healthcare information has been particularly rapid in diagnostic and therapeutic technologies.1,3 The development of computer-based bibliographies has made it easier to make use of the published literature, simply and relatively cheaply. Furthermore, the publication of clinical guidelines, such as those from the National Institute for Health and Care Excellence (NICE), aid busy clinicians who may not have sufficient time to study the primary research.

EBM is now widely taught in medical schools. Groups such as the Cochrane Collaboration and the Centre for Reviews and Dissemination in York, England co-ordinate and publish systematic reviews of the effects of healthcare, and a variety of evidence-based practice journals have been launched.2

The practice of evidence based medicine involves five essential steps: 3, 4

  1. Formulating answerable clinical questions – this may relate to diagnosis, prognosis, treatment, iatrogenic harm, quality of care, or health economics
  2. Systematic retrieval of the best evidence available.
  3. Critically appraising the evidence (determining the validity and applicability).
  4. Applying the evidence (directly in-patient care, or in the development of protocols and guidelines).
  5. Evaluating performance.

Advantages of EBM1

  • EBM allows clinicians and patients access to the most recent clinical knowledge
  • EBM can be learnt by people from different backgrounds and at any stage in their careers.
  • EBM has the potential to improve continuity and uniformity of care through the development of common approaches and guidelines
  • It can help providers make better use of limited resources by enabling them to evaluate clinical- and cost-effectiveness of treatments and services

Disadvantages of EBM1

  • EMB takes time to both learn and practice
  • Establishing the infrastructure for practicing EBM costs money, for example buying and maintaining suitable computer systems
  • EBM exposes gaps in the evidence. However, this can also be helpful in generating local and national research projects
  • Medline and the other electronic databases are not comprehensive and are not always well indexed
  • EBM can be adversely affected by publication bias, or by a lack of evidence
  • EBM is not a drive towards formulaic medicine. A clinician should listen to the patient, use their own clinical judgement, and be mindful of the best available evidence, so that the optimum management plan is identified for that patient.



  1. Rosenberg W, Donald A. Evidence based medicine: an approach to clinical problem-solving. BMJ 1995;310:1122-1126.
  2. Sackett, DL, Rosenberg W, Muir Gray JA et al. Evidence-Based Medicine: What it is and what it isn't. BMJ 1996:312:71-72.
  3. Dawes M, Summerskill W, Glasziou P et al. Sicily statement on evidence based practice. BMC Medical Education 2005, 5:1.
  4. Porzsolt F, Ohletz A, Thim A et al. Evidence-based decision making - the six step approach. Evidence Based Medicine 2003;8:165-166.
  5. Muir Gray JA. Evidence-based healthcare: how to make health policy and management decisions. London: Churchill Livingstone, 1997.
  6. Akobeng AK. Principles of evidence based medicine. Archives of Disease in Childhood 2005;90:837-840


Further Resources

Evidence based medicine on the web

Evidence Based Medicine Journals




© Helen Barratt, Maria Kirwan 2009, Saran Shantikumar 2018